From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- net/ipv6/protocol.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 net/ipv6/protocol.c (limited to 'net/ipv6/protocol.c') diff --git a/net/ipv6/protocol.c b/net/ipv6/protocol.c new file mode 100644 index 000000000..d4b1806ba --- /dev/null +++ b/net/ipv6/protocol.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * PF_INET6 protocol dispatch tables. + * + * Authors: Pedro Roque + */ + +/* + * Changes: + * + * Vince Laviano (vince@cs.stanford.edu) 16 May 2001 + * - Removed unused variable 'inet6_protocol_base' + * - Modified inet6_del_protocol() to correctly maintain copy bit. + */ +#include +#include +#include +#include + +#if IS_ENABLED(CONFIG_IPV6) +struct inet6_protocol __rcu *inet6_protos[MAX_INET_PROTOS] __read_mostly; +EXPORT_SYMBOL(inet6_protos); + +int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol) +{ + return !cmpxchg((const struct inet6_protocol **)&inet6_protos[protocol], + NULL, prot) ? 0 : -1; +} +EXPORT_SYMBOL(inet6_add_protocol); + +int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char protocol) +{ + int ret; + + ret = (cmpxchg((const struct inet6_protocol **)&inet6_protos[protocol], + prot, NULL) == prot) ? 0 : -1; + + synchronize_net(); + + return ret; +} +EXPORT_SYMBOL(inet6_del_protocol); +#endif + +const struct net_offload __rcu *inet6_offloads[MAX_INET_PROTOS] __read_mostly; +EXPORT_SYMBOL(inet6_offloads); + +int inet6_add_offload(const struct net_offload *prot, unsigned char protocol) +{ + return !cmpxchg((const struct net_offload **)&inet6_offloads[protocol], + NULL, prot) ? 0 : -1; +} +EXPORT_SYMBOL(inet6_add_offload); + +int inet6_del_offload(const struct net_offload *prot, unsigned char protocol) +{ + int ret; + + ret = (cmpxchg((const struct net_offload **)&inet6_offloads[protocol], + prot, NULL) == prot) ? 0 : -1; + + synchronize_net(); + + return ret; +} +EXPORT_SYMBOL(inet6_del_offload); -- cgit v1.3.1